Why do HRIAs (Historic Resource Impact Assessments)?

“Archaeological heritage is an essential element in the affirmation of our Canadian identity and a source of inspiration and knowledge. It is the policy of the Government of Canada to protect and manage this heritage.1

This sentiment is echoed through all levels of government and most provinces2, territories, and municipalities have either a piece of legislation, regulation, policy, or official plan in place that enables the government to protect heritage resources on lands within its jurisdiction.

For example, it’s stated in Alberta’s Historical Resources Act that when the Minister thinks a proposed operation or activity is likely to alter, damage, or destroy a historic resource, the Minister may order that person to undertake an HRIA3. This means that the Minister of Alberta Culture and Tourism (ACT) has the authority to require developers to conduct studies that assess the potential impacts of their development on historic resources. In Alberta, these studies are called “Historic Resources Impact Assessments” or HRIAs.

If the HRIA determines that there are historic resources located within the development footprint that may be impacted by the proposed development, ACT may require that the impacts be mitigated before the project will receive development approval (i.e. through modification of the development plan or the completion of a Historic Resource Impact Mitigation / HRIM). The goal of HRIA and HRIM studies is to ensure that significant historic resources are preserved through the development and land use planning processes. As such, the Minister may require the authority responsible for approving the proposed development (such as Alberta Environment and Parks, Agriculture and Forestry, or the Alberta Energy Regulator) to withhold or suspend the approval (or licence/permit/etc.) until the HRIA/HRIM requirements have been satisfied.

Have you been required to obtain a permit-status archaeologist to undertake an HRIA/HRIM? We’d be happy to discuss how Tree Time Services can best help you through the approvals process so you can focus on your core business. Call Kurt at 780-472-8878 or email [email protected].

1 Archaeological Heritage Policy Framework, Department of Canadian Heritage, Ottawa, 1990.

2 “We value the natural heritage and human history of Alberta because they help us understand and value the past on which our present is built, and give us a deepened awareness of our common roots and shared identity.” The Spirit of Alberta: Alberta’s Cultural Policy, 2009:3

3 Alberta’s Historical Resources Act, Section 37.2

What is Mitigative Excavation?

Mitigative excavation is the process of digging an archaeological site that is threatened either by development or natural erosion. Mitigative excavations have different goals than academic excavations. The goal of mitigative excavations is is to save as much information about the site before it is destroyed, whereas in academic digs the goal is to answer specific questions about how people were using the site in the past.

When a planned development is in direct conflict with a significant archaeological site our normal first recommendation is for a project redesign in order to avoid impacting the site. When a project redesign is not a viable option a mitigative excavation might be required.

Before the excavation begins additional shovel testing may be required to ensure that the boundaries of the site have been confidently established and to identify the most important or valuable part of the site. Using what we have learned from the shovel testing we select areas for excavation blocks. We try to target the places where we’ll get the best return, in scientific information, for the investment of time. These excavation blocks are usually excavated in 1×1 m units. During the excavation layers of a predetermined depth are carefully removed. The sediment is screened and artifacts are collected. While excavating each layer is carefully described and locations of artifacts within the layer are recorded. Any changes in the soils or unusual staining is also described in detail. As each layer is removed photos are taken to further document the process. Once the unit is excavated to its final depth photos and drawings are taken of the unit walls. These photos and drawings will help us to understand the natural formation of the site area by studying the statigraphy. Looking at the layers of the soil can help us to determine if some artifacts in the site are older than others and can help us to understand how long or often the site was used by people in the past.

Mitigative excavations in Alberta typically do not involve excavation of the entire site as you might see in academic research excavations; instead archaeologists first consult with the developer and the government and excavate a sample of the site that focuses on the area of impact, and maximizes the information value of the dig.

Once the mitigative excavation is complete and the final report describing the project has been approved by the government the development will be allowed to proceed.

Mitigative excavations usually move along at a faster pace than academic excavations. This is related to time restrictions associated with development planning and budgetary concerns, as well as our focus on efficiency, and maximizing the return on investment. Academic excavations often take place over many field seasons but mitigative excavations have to be completed before the developer begins construction.

Mitigative excavation is our best tool to preserve archaeological heritage when avoidance isn’t an option, but it’s still a net loss in heritage value. Archaeological sites are non-renewable resources, once they have been destroyed, whether by excavation or development, no more information can be collected about the site.

Introduction to CRM Part 5: Reporting

Once we have surveyed our targets and evaluated any sites we have found, it is time to return to the office. All of our notes are taken on an ipad in the field. Now all we have to do is export our notes into a database which eliminates the hours spent on data entry.

Note taking is extremely important for archaeologists (Figure 1). The notes supply researchers the context of the artifacts. In this case context means the precise location of the artifact and it’s association with other artifacts and landscape features. This helps researchers determine such things as the relationships between artifacts on a site, it’s position in time and space, and even how it is related to different archaeological sites (Figure 2). Without notes and proper excavation methods, the context in which the artifacts were found is lost forever, and the artifacts have little scientific or interpretive value.

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Figure 1. Eric taking notes on an iPad that will later be used to interpret the site.
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Figure 2. An artifact in it’s original context found at an historic site.

We also catalogue all of the artifacts that were collected in the field. We take measurements, weights, and note details such as material and artifact types, and enter them into a database (Figure 3). This along with the site notes gives us the information we need to write our reports.

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Figure 3. Madeline is weighing an artifact.

In the final stage of the Historic Resources Impact assessment, we compile a report of all the work that we have done and submit it to our clients and the government. The report identifies which developments need to be modified to avoid impacting significant archaeological and historic resources. The site information is included in a government database of all the sites in Alberta as a reference for future industry development as well as researchers. This minimizes the impact that our clients have on Alberta’s history while preserving the past for future research and education.

Introduction to CRM Part 4: Evaluating a Site

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Figure 1. Positive shovel test that contained lithic debitage.

When we identify a site, we conduct further evaluative testing to determine the type, character, and extent of the site. This is done according to government guidelines, and depends on the type of site, and the type of landform. If the landform allows for it, testing occurs in each cardinal direction or in a grid. Some sites are found on ridges or point terraces, and so in these cases, it is not possible to test in all directions (Figure 1).

Tree Time’s standards are that there must be three negative tests spaced at most 10 m apart in each direction from any positive. Sometimes additional tests are required in order to determine the significance, the size, and type of the site. For example if none of the evaluative tests were positive, further testing might be done at closer intervals to better determine the significance of the site. In addition to rigorous note taking, we also map and photograph the site (Figure 2).

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Figure 2. Vince taking notes at a site.

The evaluation of the site is an important step for two main reasons. The first is to enable the government to maintain an accurate site database and to better inform future researchers of the size and type of sites are in the area (Figure 3).

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Figure 3. We are evaluating an historic site by flagging artifacts with red flagging tape.

Secondly, in this stage we determine the extent and significance of the site. If a client decides to avoid the site, delineation allows us to more precisely buffer the site. This is important because it allows the development to occur as close to the original plan as possible while still avoiding impacts to the site. In addition, if a client chooses to mitigate their impacts to the site through excavation, a more detailed evaluation of a site allows us to better predict the productivity of the site, and to render cost estimates of any mitigation work more accurately.

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Figure 4. Buffer flagged around the site with orange flagging tape.

Once we have surveyed our targets, evaluated any sites we have found, and have finished our notes, it is time to return to the office (Figures 5 and 6).

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Figure 5. Reid is finishing his notes before we move onto another target.
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Figure 6. After a long cold day, Brittany heads back to the office.

Introduction to CRM Part 3: Archaeological Survey

Using information compiled in the office, the next step of an HRIA is to leave the comforts of home behind and to venture into the field. Although there is a perception of archaeologists working at large excavations, often dressed in khakis and maybe wearing a fedora, archaeological survey is the most common type of field work in the CRM sector. So for now, we will focus on archaeological survey and discuss archaeological mitigation in an upcoming blog.

The purpose of an archaeological survey is to visit the high potential target areas we identified in our background research and GIS review in order to see if there are any historic or archaeological sites. We travel to these high potential locations using various means of transport including trucks, ATVs, Argos, the occasional helicopter for the most remote locations, and a lot of hiking (Figures 1 and 2).

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Figure 1. Teresa and Vince in an Argo travelling to target areas.
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Figure 2. Archaeology happens in all weather as Teresa and Brittany hike in snow to our target areas.

When we arrive at these locations, we use experience and expertise to determine if the landform has potential for archaeological and historic sites. For example, is this spot flat and dry? Would we like to camp or hunt from here? High, dry areas, and spots that have nice views are often tested. In fact sometimes we identify a site in the exact spot where we dropped our gear for lunch, as we naturally tend to stop on the best part of the landform (Figure 3).

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Figure 3. Our gear placed at a positive shovel test, flagged with red flagging tape.

 

The most common method of subsurface sampling that we use is screened shovel tests (Figure 4). This means we dig holes about 40 cm square and 30 to 40 cm deep and screen all of the sediment in portable screens. If there are any tree throws or surface exposures, we also conduct opportunistic examinations of these for artifacts (Figure 5).

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Figure 4. Matt is shovel testing.
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Figure 5. Picture of a tree throw that allows for opportunistic sampling.

There are several different sampling strategies that we use, these include systematic, semi-systematic, and judgmental testing. Systematic testing is the term we use when we place tests using a set interval, for example digging a test every 10 m along a landform. For judgmental testing we do not use a set interval instead we place shovel tests on the best part of a landform based on our past experience and conceptual models of how people lived on different types of landforms. Finally, semi-systematic testing is a combination of the previous two. For this method we place tests on the best locations of a land-form while trying to maintain a certain overall density of testing.

The shape of the landform helps determine what type of sampling strategy to use to test a target. A long uniform ridge might be better suited for hybrid or systematic testing, while a hillock might be more often tested in a judgmental manner (Figure 6).

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Figure 6. Brittany testing a target using a semi-systematic strategy.

If the tests are negative, then we write our notes and move on to another location to survey. However, this does not mean that we can definitely say there is not a site at the location. Negative results only reduce the chance there’s a site at a location. To be 100% sure, we’d have to do a lot more excavation (Figure 7).

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Figure 7. Although a nice area near water, we did not identify a site here.

On the other hand when we do identify a site, then we stay at the location to undertake further evaluative testing (Figure 8).

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Figure 8. Vince is very happy after identifying a site when he found a point in a shovel test.

Introduction to CRM Part 2: Development Screening and Project Planning

The first step of a historic resources impact assessment (HRIA) happens in the office. Once we have the plan for a development, we need to assess whether the footprint will impact any recorded sites or if it has the potential to impact any unrecorded sites. We use our experience and knowledge of archaeology, GIS data, and databases of recorded sites in order to identify high potential areas that might have any archaeological and historic resources (Figure 1). Although this stage of archaeology does not capture the imagination of the public and isn’t very exciting or glamorous, it is the most important part and the foundation of our work.

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Figure 1. Corey is targeting areas of high potential using QGIS.

High potential areas vary by region, depending on the geography and the history of the area. Generally areas that people would camp or travel through are considered high potential; these include well-defined landforms and areas near water. We also take into account the environment of the past. For example, shorelines fluctuate, and rivers and streams may change course or dry up. Areas near water generally have higher potential because they were used as a method of transport, offered fishing opportunities, and, of course, they were also a source of fresh water (Figure 2).

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Figure 2. View from an archaeological site looking towards a lake.

Sometimes a development plan will conflict with a previously recorded site. In this case, we can recommend either that the development plan be changed to avoid the site, or that impacts to the site be mitigated by excavation. If there are no recorded sites in the footprint, but there are areas that we think are likely to have sites, we recommend field survey. Using GIS data and the research that we have complied concerning the area around the developmental footprint, we create targets of high potential areas to survey in the field. The next step takes us out of the office and into the field.

Introduction to CRM Part 1: Cultural Resource Management

Cultural Resource Management (CRM) is undertaken in many different countries all over the world and it can go by just as many names, Contract Archaeology, Consulting Archaeology, Compliance Archaeology, and Heritage Resource Management (HRM) to name a few. Whatever CRM is called, the underlying purpose is always the same. These archaeologists engage in the protection, preservation, and professional management of archaeological and historic sites. In Canada, this means that we help minimize any impacts planned developments might have on a province’s archaeological and historic resources. These resources include archaeological sites containing artifacts such as stone tools and animal bones (Figure 1), and historic sites consisting of structures like cabins or artifacts like metal tools (Figure 2).

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Figure 1. A stone knife that was recovered from a pre-contact (prehistoric) site.
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Figure 2. A cabin that we discovered during an archaeological survey.

Using our experience in archaeology and research, along with computer programs like GIS, we review development plans and identify recorded sites and areas that have high potential to have archaeological and historical resources (Figure 3). This most commonly results in an archaeological survey of the high potential areas. Another option is to move a development or minimize the potential impacts by changing the way the development will be done.

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Figure 3. Corey is identifying high potential areas using GIS.

Next, we go into the field to survey the high potential areas (Figure 4). In forested parts of Alberta we do this by shovel testing. If we identify a site, we dig more evaluative tests to determine the nature and extent of it. This allows us to contribute information for the government and other researchers concerning the size and type of sites in the area. In addition, it allows us to more precisely buffer the site for our clients so development can occur close to the site without impacting it. It also makes it possible for us to better evaluate the significance of the site and to render cost estimates for any mitigation work much more accurately.

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Figure 4. Teresa is taking notes about a site.

 

Once we complete the field survey, we return to the office. This is where we catalogue the artifacts and compile a report for our clients and the government.